This paper presents a pipeline in progress for generating virtual 3D model of urban street facades by fusing cadastral map with terrestrial images and laser data. A Mobile Mapping System (MMS) has been employed to massively gather georeferenced images and laser raw data at street level. Firstly, we describe the context as well as our motivation that aims at enriching the quality of the virtual urban environments. Secondly, we briefly present advanced works on 3D street facades mapping by merging the cadastral map and laser data. These works addressed the street facade plane estimation, their delimitation, and their texturing. Thirdly, we present a novel extension we are working on for extracting 3D detailed facade limits by fusing the cadastral map with laser and image data. This extension is essentially focused to the detection of fine 2D skylines from acquired high resolution facade images and to the estimation of the detailed 3D facade top boundaries. The presented work deals with datasets acquired in the city of Paris under real conditions. Advances and results show the potential of the envisaged pipeline for applications such as the visualization and the large scale navigation in virtual 3D street model.